The guidance on what to do if you think you might be suffering from swine flu is very clear – stay in your home and away from anyone else you think you might infect.

Potential sufferers of swine flu have been told to ring NHS Direct or check their symptoms on the online "flu symptom checker" to see if there is a chance they might have the virus.

A careful list of criteria has been drawn up by the Department of Health and is available on its website.

Of interest, is anyone who has been to Mexico or San Antonio, Texas, San Diego, Imperial County or New York City in America in the last seven days.

Also of concern, is anyone who has pain in or across their chest, pain in their shoulder, is short of breath, has swelling around the lips, mouth or tongue or has lips, fingernails or toenails which are changing colour.

Anyone with such symptoms is urged to call 999 immediately and asked not to leave their homes.